Attention has heretofore been paid to a semiconductor power device for use chiefly in a system, such as a motor control system or a power conversion system, in various power electronics fields.
For example, FIG. 1 of Patent Literature 1 (PTL 1) discloses a Schottky barrier diode in which SiC is employed. This Schottky barrier diode is composed of an n type 4H-SiC bulk substrate, an n type epitaxial layer grown on the bulk substrate, an oxide film that is formed on a surface of the epitaxial layer and by which the surface of the epitaxial layer is partially exposed, and a Schottky electrode that is formed in an opening of the oxide film and that makes a Schottky junction with the epitaxial layer.
Additionally, FIG. 4 of Patent Literature 1 discloses a vertical MIS field-effect transistor in which SiC is employed. This vertical MIS field-effect transistor is composed of an n type 4H-SiC bulk substrate, an n type epitaxial layer grown on the bulk substrate, an n type impurity region (source region) formed on a surface part of the epitaxial layer, a p type well region formed contiguously to both sides of the n type impurity region, a gate oxide film formed on a surface of the epitaxial layer, and a gate electrode that faces the p type well region with the gate oxide film therebetween.